Powered clamp closure mechanism

ABSTRACT

A powered clamp assembly for use on managed pressure drilling rig comprising:
         a first jaw and a second jaw, each one of said jaws comprising a pivot extremity and a locking extremity, each one of said pivot extremity comprising a structural member jutting outwardly from its respective jaw and pivotally connected to a bridging means;   each one of the locking extremities is connected to one another through a closure means;   wherein the movement of said first jaw and said second jaw allows movement of said jaws between a proximal position in relation to each other and a distal position.

FIELD OF THE INVENTION

The present invention relates to a powered clamp for use in the oil andgas industry, more specifically a hydraulic clamp used in managedpressure drilling operations.

BACKGROUND OF THE INVENTION

When drilling for oil and gas, one encounters geological formations thathave a narrower tolerance for changes in bottom hole pressure. A widelyadopted solution to this problem is the so called ‘Managed PressureDrilling’ (MPD). In this method of drilling, the annular space is closedto the atmosphere by means of a Rotating Control Device (RCD). An RCD isa pressure-control device used during drilling for the purpose of makinga seal around the drillstring during its rotation and/or tripping in andout of a well. The RCD is designed to contain or divert hydrocarbons orother wellbore fluids and pressure and prevent their release to theatmosphere. The RCD diverts the fluid into a manifold equipped with aspecialized choke that allows manipulation of the well's bottom holepressure. Right before breaking a connection to add a new stand, thepumps are ramped down. At the same time, the dynamic component of thebottom hole pressure drops and needs to be compensated for, in order tomaintain a near-constant bottom hole pressure.

In the oil and gas industry, it is paramount to ensure the safety ofemployees, a problem that may jeopardize employees' safety on a drillingrig is known as a “blowout”. When a zone of high geopressure isencountered during a drilling operation and the pressure exceeds thehydrostatic pressure exerted by the drilling mud, and the formation hassufficient permeability to allow fluid flow, then the formation fluidwill move into the wellbore and displace the drilling mud. This isreferred to as a “kick”; and if unchecked it will result in a “blowout”which is an uncontrolled release of crude oil and/or natural gas from anoil well Through the use of an MPD system which includes an RCD a kickcan be safely controlled.

U.S. Pat. No. 9,163,473 discloses a RCD which includes a housingassembly which contains a bearing assembly and an annular seal whichrotates and seals off an annulus between a tubular string and an RCDbody, a remotely operable clamp device which selectively permits andprevents relative displacement between the housing assembly and thebody, and a remotely operable safety latch which selectively permits andprevents unclamping of the clamp device. A method of remotely operatingan RCD clamp device can include remotely operating a safety latch whichselectively permits and prevents unclamping of the clamp device, andremotely operating the clamp device while the safety latch is in anunlatched position, thereby unclamping a bearing housing assembly fromthe RCD body. Another RCD can include a remotely operable clamp devicewhich selectively permits access to an RCD body interior, and a remotelyoperable safety latch which selectively prevents unclamping of the clampdevice.

Despite the existing prior art, there still exists a need for a robust,reliable powered clamp assembly to seal the wellbore from the atmosphereduring managed pressure drilling. Preferably, such hydraulic clampshould also be operable remotely to increase the personnel's safetyaround the wellbore.

Most of the existing art that exists around RCD clamps still result inhaving a person atop the annular BOP to install a safety pin or means ofensuring the clamp remains closed in the event of loss of hydraulicpressure. Manual clamp technology causes an operator to place a personatop the annular so as to open/close the manual clamp which in turnintroduces a significant safety concern especially when dealing withhydrocarbons and pressure. Preferably such a hydraulic clamp should alsoinclude a safety mechanism or method that ensures the clamp remainsclosed in the event of the loss of hydraulic pressure.

SUMMARY OF THE INVENTION

Accordingly, there is provided a powered clamp assembly for use on anRCD which allows the RCD and accessories to be installed or retrievedwithout having to have personnel atop the annular BOP during criticaloperations.

According to an aspect of the present invention there is provided apowered clamp assembly for use on an RCD comprising:

a first jaw and a second jaw, each one of said jaws comprising a pivotextremity and a locking extremity, each one of said pivot extremitycomprising a structural member jutting outwardly from its respective jawand pivotally connected to a bridging means;

each one of the locking extremities is connected to one another througha closure means;

wherein the movement of said first jaw and said second jaw allowsmovement of said jaws between a proximal position in relation to eachother and a distal position.

According to a preferred embodiment of the present invention, there isno need for a safety pin or any additional manual safety device.Position locking with a failure of the external power source is achievedthru trapping operating pressure in the locking actuator as well as thrufriction from operating loads.

According to a preferred embodiment, the closure means maintains contactwith the locking extremity of each one of said first and second jaw whensuch are in said distal position in relation to each other.

According to a preferred embodiment, the closure means is selected fromthe group consisting of: a threaded screw mechanism; a latch mechanism;and a double clasp mechanism.

According to a preferred embodiment, the closure means are actuatedremotely. Preferably, the powered clamp assembly further comprises asecond closure means. Preferably, the powered clamp assembly furthercomprises a threaded screw mechanism connecting the closing extremitiesof said first and second jaw together and a double latch mechanism.

According to an aspect of the present invention, there is provided apowered clamp assembly for use in managed pressure drilling which isexpandable through a combination of a pivot and articulations between asubstantially open position and a substantially closed position. One ofthe advantages of the present invention is the capacity to maintain thealignment of a first jaw and a second jaw, upon opening so that uponclosure said first and second jaw are in alignment. Said first jaw andsecond jaw each having a first extremity and a second extremity, whereinsaid first extremity of said first jaw and said second jaw arepositioned proximate one another, and wherein the second extremity ofsaid first jaw and said second jaw are in abutment with one another whensaid hydraulic clamp is in a closed position and second extremity ofsaid first jaw and said second jaw are spread apart when said hydraulicclamp is in an open position.

According to a preferred embodiment, each one of said first and secondjaw are pivotally mounted to a pivot point. Preferably, each one of saidfirst and second jaw are pivotally mounted to a first and a second pivotpoint respectively. Preferably, the first and second pivot points arepositioned proximate each other. Preferably, each jaw covers half of thecircumference of a tube on which it is applied. More preferably, eachjaw has a hemicircular shape in order to adapt to the contour of thetube upon which it will be applied and be tightened. Preferably, eachjaw's shape is adapted to form a tight lock on the tube upon which it ismeant to be tightened and be complementing of each other' s geometry tosurround the entirety of the tube' s circumference.

According to a preferred embodiment of the present invention, the secondextremity of said first jaw and second jaw are secured together using abreech lock. Preferably, the second extremity of said first jaw andsecond jaw are maintained in permanent connection with one anotherthrough threaded screw part of the breech lock. This is combined with atoggle latch to provide additional security when locking the clampassembly. Preferably, the toggle latch is a double toggle latch. Theprimary locking means can be described as a “breech lock”. The breechlock consists of an externally threaded rod and internally threadedsocket which have part of the threads removed so they can mate.According to a preferred embodiment of the present invention, when inoperation, the socket is actuated in a non-continuous rotary motion ofapproximately 90 degrees while the rod is stationary. The pitch of thethreads combined with the rotation causes the latch to tighten.

According to a preferred embodiment of the present invention, a featureof the powered clamp assembly is that there is no need for a safety pinor any additional manual safety device. This is achieved through theself-locking nature of the threaded rod/socket interface as well as theability to maintain pressure applied to the rotary actuator.

According to a preferred embodiment of the present invention, the meansof load holding and closure are two separate items. The linkage andcylinder arrangement which is used only to open/close the two clamphalves, and the breech lock which is the primary load holding andlocking apparatus. Preferably, the linkage can be described as a linkagewhich can be acted on by any sort of linear actuator(s) (be ithydraulic, electric, etc.) and a breech lock which can be operated by arotary actuator (but not a motor as used in the reference patent). It isimportant to note the difference between a rotary actuator and a motoras it is an important distinction. A rotary actuator as described hereinhas a limited range of motion with physical stopping points. Usually 90or 180 degrees, as contrasted with a motor which has no physicalrotation limits. The prior art device mentioned earlier disclose acontinuous rotation motor. Moreover, a breech lock functions with 90degrees (or less depending on the design) of rotational movement wherethe screw mechanism in the prior art patent requires continuous rotationto function.

According to a preferred embodiment of the present invention, the clampsections are moved to either the open or closed position by thelinkage/linear actuators. That is their only function. The cylinders arenot load-bearing or position-locking. The prior art device discussedpreviously, requires that the cylinder or screw mechanism fulfills boththe functions of movement and load bearing. Accordingly and to reducethe possibility of breakage, a preferred embodiment of the presentinvention comprises a breech lock as the only load bearing member andwhich, moreover, does not contribute to clamp movement to or from openand closed.

BRIEF DESCRIPTION OF THE FIGURES

The detailed description will be better understood in conjunction withthe accompanying drawings as follows:

FIG. 1 is a front perspective view of the powered clamp according to apreferred embodiment of the present invention in a closed position;

FIG. 2 is a back perspective view of the powered clamp according to apreferred embodiment of the present invention in a closed position;

FIG. 3 is a front perspective view of the powered clamp according to apreferred embodiment of the present invention in an open position; and

FIG. 4 is a back perspective view of the powered clamp according to apreferred embodiment of the present invention in an open position.

BRIEF DESCRIPTION OF A PREFERRED EMBODIMENT

As seen in FIGS. 1 to 4 , the powered clamp assembly (10) according to apreferred embodiment of the present invention comprises a first (20) anda second jaw (30). Each one of said jaws comprising a pivot extremity(22, 32) and a locking extremity (24, 34). Each one of said pivotextremity (22 and 32) comprising a member (25, 35) jutting outwardlyfrom the jaw (20, 30) and pivotally connected to a bridging means (40)through a pin (26, 36) or any equivalent mechanical component whichpermits rotation. Optionally, and as illustrated, the bridging means(40) may comprise a second bridging element (42) located under themembers (25, 35). Alternatively, the bridging means may extend from thetop side (27, 37) of the members (25, 35) to the bottom side (not shown)as a single piece. According to an alternative embodiment, the bridgingmeans can comprise a single pivot point onto which both members jutthereonto.

As shown in the preferred embodiment, the locking extremities (24, 34)of the jaws (20, 30) are in permanent connection with one anotherthrough a double clasp mechanism (50) which allows the opening andclosing of the jaws all the while maintaining them in alignment. Correctalignment of the two jaws upon closure of the clamp is highly desirableas the internal surfaces of each jaw must contour the tubing with asmuch surface as possible to ensure effectiveness of the clamp. Thus, theinner circumferential shape created by the first and second jaw when ina closed position should be such that it frictionally engages the tubearound which it is disposed. Preferably, the profile of the clampsmatches the profile formed by the body neck and RCD or accessory.According to a preferred embodiment and as shown in FIGS. 3 and 4 , onenotes that the internal surface of the jaws is not flat but rather ithas grooves (80 and 90) adapted to contour a specific type of RCD and/oraccessories set-up. The internal surface of the jaws (grooves or nogrooves) in no way affects how the clamp assembly operates, it justdetermines RCD body, RCD, and accessory compatibility.

The closing mechanism is a double latch mechanism (50) comprises a link(51) connecting the two symmetrical latch assemblies together. Eachlatch assembly is connected to its respective locking extremity (24, 34)through member (52, 52′). Member (52) is pivotally connected at pivotpoint (53, 63) an element (54, 64) which also rotates at point (55, 65).Member (52) is in connection with element (56) through pivot point (55,65) and in rotational connection with link (51) through the two-partpivot point (57). Meanwhile, element (56) also has a pivot connection(not shown) with link (51) to allow for the toggle latch to operate assuch.

According to the illustrated embodiment, the closing mechanism is adouble latch mechanism (50) and is equipped with a second lockingmechanism comprising a threaded screw mechanism (60) connecting thelocking extremities (24, 34) of each jaw together over and above thedouble latch mechanism. According to the illustrated embodiment in FIG.4 , the threaded screw mechanism (60) employs a threaded screw (70)having a threaded portion (72) which portion has a non-threaded section(74). The non-threaded section (74) allow for the mechanism (60) to slipover the threaded screw (70) more easily prior to tightening of themechanism (6) to ensure a secure locking of the jaws together during theperformance of the hydraulic clamp assembly (60).

Preferably, the powered clamp comprises an actuator to move the two jawsbetween a first closed position (see FIGS. 1 and 2 ) where the clamp isfully shut and a second position where the two jaws are in an openposition where their respective locking extremity are in a positiondistal from each other (see FIGS. 3 and 4 ). Preferably, the actuatorcan be mechanically driven, electrically-driven or hydraulically-driven.An actuator operates the mating socket displacement onto and along thethreaded screw to tighten or release the jaws. Preferably, also, thelatch clasp may also be activated through the operation of a secondactuator. This allows the operator to remotely operate the hydraulicclamp and heighten the security of workers. Moreover, it is believedthat only one of the two locking mechanisms (latch and threaded screw)is necessary to maintain the two jaws in alignment. The redundancy ofthis preferred embodiment increases the safety of its use in variousoperations and allows operators to remotely operate the clamp.

As seen in FIGS. 3 and 4 , the locking mechanism is a latching mechanismand is made up of a sequence of articulated elements acting in concertto perform a latch closure. The latching mechanism is believed to behighly desirable as it can provide a safe closure all the whileproviding the operator to actuate it remotely. Preferably, the latchmechanism permanently connects the jaws to each other and thereforeensures the alignment thereof when the clamp is closed. In addition toremote operation, position indication sensors are used to remotelyindicate the status of the two operation stages with either “open” or“closed”. This removes the need for visual confirmation of apparatusposition which also enhances safety and operational efficiency.

According to a preferred embodiment, there is no need for a safety pinor any additional manual safety device. This is achieved through theself-locking nature of the treaded rod/socket interface as well as theability to trap pressure applied to the rotary actuator.

According to a preferred embodiment, the clamp assembly comprises twofactors which negate the need for a safety latch. One being the threadgeometry selected for the main rod/nut is inherently self-locking, theother factor being that the hydraulic valving used is directly mountedto the rotary actuator which will prevent any movement until theactuator direction is reversed. This can be achieved since the rotaryactuator in question has no internal leakage (as compared to a motor,which does have internal leakage).

According to a preferred embodiment, one of the means of motion toachieve clamp opening and closing is using opposing dual actingcylinders as compared to a screw drive in the prior art documentdiscussed earlier. According to a preferred embodiment of the presentinvention, the open/close cylinders move the clamp through a linkagewhich allows the powered clamp assembly to be much more compact when inthe closed position and shields the moving parts from any possibledamage which could be potentially caused by impacts from other objectsbeing lifted or moved. Contrary to the prior art, where the mechanismdisclosed has the primary load acting through the open/close cylinder,in a preferred embodiment of the present invention, the primary loadnever goes through the movement cylinders. This is one of the reasonsthe clamp assembly according to a preferred embodiment of the presentinvention is compact.

According to a preferred embodiment of the present invention, when inuse the clamp can be tightened around a tube remotely either wirelesslyor through a cable connected to the powered clamp. The operator, whichis located at a safe distance from the wellbore and hence the poweredclamp, enters instructions or operates controls which are meant torelease the lock mechanism, once the lock mechanism has been operated,the closure is opened and the clamp's grip is loosened to allow the RCDor accessories to be removed or installed into the RCD body.

As is understood by the person skilled in the art to which thisdisclosure is addressed, the pivot extremity, the locking extremity, andthe locking mechanism can take different forms but still be consideredto be part of the inventive concept as described and illustrated herein.The embodiments described herein are to be understood to be exemplaryand numerous modification and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the claims appended hereto, theinvention may be practiced otherwise than as specifically disclosedherein.

1. A powered clamp assembly for use on a rotating control device on amanaged pressure drilling rig comprising: a first jaw and a second jaw,each one of said jaws comprising a pivot extremity and a lockingextremity, each one of said pivot extremity comprising a structuralmember jutting outwardly from its respective jaw and pivotally connectedto a bridging means; each one of the locking extremities is connected toone another through a closure means; wherein the movement of said firstjaw and said second jaw allows movement of said jaws between a proximalposition in relation to each other and a distal position.
 2. The poweredclamp assembly according to claim 1 wherein said closure means maintainscontact with the locking extremity of each one of said first and secondjaw when such are in said distal position in relation to each other. 3.The powered clamp assembly according to claim 1 further comprising aload holding and locking means selected from the group consisting of: athreaded screw mechanism; and a breech lock mechanism.
 4. The poweredclamp assembly according to claim 1 wherein said closure means areactuated remotely.
 5. The powered clamp assembly according to claim 1wherein the closure means comprise a linkage and cylinder arrangement.6. The powered clamp assembly according to claim 1 wherein the linkageand cylinder arrangement is solely used only to open/close the two clamphalves
 7. The powered clamp assembly according to claim 1 wherein themeans of load holding/locking and closure are two different components.8. The powered clamp assembly according to claim 1 wherein the linkageis operated by a linear actuator.
 9. The powered clamp assemblyaccording to claim 1 wherein the linkage is operated by a linearactuator selected from the group consisting of: a hydraulic actuator; anelectric actuator; and a mechanically-driven actuator.
 10. The poweredclamp assembly according to claim 1 wherein the load holding and lockingmeans is operated by a rotary actuator.
 11. The powered clamp assemblyaccording to claim 3 wherein the load holding and locking means isoperated by a rotary actuator selected from the group consisting of: ahydraulic actuator; an electric actuator; and a mechanically-drivenactuator.
 12. The powered clamp assembly according to claim 1 furthercomprising a threaded screw mechanism connecting the closing extremitiesof said first and second clamp jaw.
 13. The powered clamp assemblyaccording to claim 1 wherein a threaded screw mechanism comprises thesole load holding and locking component associated with the closure ofsaid clamp.
 14. The powered clamp assembly according to claim 1 furthercomprising an inner circumferential shape created by the first andsecond jaw when in a closed position such that it frictionally engagesthe tubing around which it is disposed.
 15. The powered clamp assemblyaccording to claim 13, where an internal surface of the first and secondjaw comprises at least one groove adapted to contour a specific type RCDaccessory set-up.